Technical Field
Embodiments disclosed herein can be related to ophthalmic illumination systems. More specifically, embodiments described herein can relate to illuminating a surgical field, such as a patient's eye, during ophthalmic procedures using an optical fiber having a tapered proximal portion. The tapered proximal portion can allow the optical fiber to efficiently receive a misaligned light beam.
Related Art
Ophthalmic microsurgical procedures can require precision cutting and/or removing of various body tissues of the patient's eye. During the procedures, ophthalmic illumination devices can provide light for the surgical field. A user, such as a surgeon or other medical professional, can insert the device into the eye to illuminate the inside of the eye. A light source and other illumination optics, such as a collimator and a condenser, direct a light beam towards an optical fiber of the illumination device.
During assembly of the illumination optics, manufacturers can try to optimize various parameters of the light beam associated with coupling the light beam into the optical fiber. For example, coupling efficiency can be a description of coupling the light beam into the optical fiber. High coupling efficiency can result in the transmission of relatively greater amounts of undistorted light from the light source to the surgical field, via the optical fiber. Low coupling efficiency can result in to less light being transmitted to the surgical field, as well as the light being transmitted with an undesired angular profile. One way of improving coupling efficiency during manufacture includes precisely aligning the illumination optics components (e.g., the collimator, the condenser, the optical fiber, etc.) and then immobilizing the components so that they do not subsequently become misaligned. For example, a beam spot of a condensed beam can be centered at the proximal end of the optical fiber upon alignment of the condenser and the optical fiber. However, any angular or lateral misalignment can cause a loss of optical coupling efficiency.
The coupling efficiency into the optical fiber can be sensitive to even small misalignments of the light beam into the condenser and/or other components. Misalignment can arise from different sources. Temperature changes during use can cause misalignment of a collimated beam into the condenser. For example, the climate surrounding the illumination optics can be atypically warm or cold, leading to thermal-induced expansion or compression of components. Vibration during use of the illumination optics can also cause misalignment. The illumination optics can be subject to mechanical shocks, such as being dropped during shipping or contacted by heavy equipment. These sources of error can be exacerbated by the inclusion of other optical components, such as fold mirrors and beam splitters. Temperature changes, vibration, and/or shock can cause the illumination optics and the light beam reflecting off of them to become misaligned. Furthermore, over the life of the illumination optics, slow creep of adhesive-based or mechanical-based mounts can cause the illumination optics and the light beam reflecting off them to become misaligned.
In some illumination optics assemblies, even angular misalignment by as little as approximately 0.01° can cause a significant decrease in the amount of light transmitted through the optical fiber. Because of the relatively high sensitivity to misalignment, maintaining high fiber coupling efficiency at all temperatures and operating conditions for the life of the illumination optics assembly can be important. An assembly that includes means of sensing and actively correcting for losses in fiber coupling efficiency by moving the condenser and/or other optical components may address some concerns. However, because of its high complexity and cost, such a coupling-efficiency sensor and active-feedback optical-alignment system would be difficult to design and implement in a cost-effective manner.
Accordingly, there remains a need for improved devices, systems, and methods that accommodate misalignment of a light beam while maintaining high coupling efficiency by addressing one or more of the needs discussed above.